#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
// #pragma GCC optimize ("Ofast,unroll-loops")
// #pragma GCC target ("avx,avx2,fma")
using namespace std;
using namespace __gnu_pbds;
typedef int ll;
typedef long double ld;
typedef pair <ll, ll> pll;
#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1);
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< x << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()
cl inf = sizeof(ll) == 4 ? (1e9 + 10) : (3e18), mod = 1e9 + 7, MOD = 998244353;
template <class A, class B> ostream& operator << (ostream& out, const pair<A, B> &a) {
return out << '(' << a.first << ", " << a.second << ')'; }
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
if(!a.size())return cout<<"[]";cout<< '[' << a[0]; for (int i = 0; ++i < (int)(a.size());) cout<< ", " << a[i];cout<< ']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;
cl N = 1e5 + 7, SQ = 150;
ll dis [N], n, m, q;
vector <ll> adj [N], jda [N], vec;
pll dp [N][SQ + 2], tmp [SQ + 2];
bool mark [N];
ll Naive (ll st, ll sz) {
ll ans = -1;
memset(dis, - 1, sizeof dis);
vec.clear();
for (ll i = 0, x; i < sz; i++) {
cin>> x;
vec.push_back(x);
}
for (auto &v : vec) mark[v] = true;
dis[st] = 0;
for (ll v = st; v >= 1; v--) {
for (auto u : adj[v]) if (~dis[u]) dis[v] = max(dis[v], dis[u] + 1);
if (!mark[v]) ans = max(ans, dis[v]);
}
for (auto &v : vec) mark[v] = false;
return ans;
}
ll solve (ll v, ll sz) {
vec.clear();
for (ll i = 0, x; i < sz; i++) {
cin>> x;
vec.push_back(x);
mark[x] = 1;
}
ll ans = -1;
for (ll i = 0; i <= SQ; i++) if (dp[v][i].sc > 0 && !mark[dp[v][i].sc]) ans = max(ans, dp[v][i].fr);
for (auto &x : vec) mark[x] = 0;
return ans;
}
void _merge (ll v, ll u) {
ll p1 = 0, p2 = 0, tot = 0;
while (tot <= SQ && dp[v][p1].sc && dp[u][p2].sc) {
if (mark[dp[v][p1].sc]) {
p1++; continue;
}
if (mark[dp[u][p2].sc]) {
p2++; continue;
}
if (dp[v][p1].fr >= dp[u][p2].fr + 1) {
mark[dp[v][p1].sc] = 1;
tmp[tot++] = dp[v][p1++];
}
else {
mark[dp[u][p2].sc] = 1;
tmp[tot++] = {dp[u][p2].fr + 1, dp[u][p2].sc};
p2++;
}
}
while (tot <= SQ && dp[v][p1].sc) {
if (mark[dp[v][p1].sc]) {
p1++; continue;
}
mark[dp[v][p1].sc] = 1;
tmp[tot++] = dp[v][p1++];
}
while (tot <= SQ && dp[u][p2].sc) {
if (mark[dp[u][p2].sc]) {
p2++; continue;
}
mark[dp[u][p2].sc] = 1;
tmp[tot++] = {dp[u][p2].fr + 1, dp[u][p2].sc};
p2++;
}
for (ll i = 0; i <= tot; i++) mark[tmp[i].sc] = 0, dp[v][i] = tmp[i], tmp[i] = {0, 0};
}
int main ()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>> n >> m >> q;
for (ll i = 0, v, u; i < m; i++) cin>> v >> u, adj[v].push_back(u), jda[u].push_back(v);
for (ll v = 1; v <= n; v++) {
dp[v][0] = {0, v};
for (auto &u : jda[v]) _merge(v, u);
}
for (ll i = 0, t, v; i < q; i++) {
cin>> v >> t;
if (t < SQ) cout<< solve(v, t) << '\n';
else cout<< Naive(v, t) << '\n';
}
return 0;
}
/*
*/
